Mechanical thermostat



FIG. 1 shows a front elevational view of the invention;

FIG. 2 shows a left side elevational view of the invention;

FIG. 3 shows a right side elevational view of the invention;

FIG. 4 shows a top plan view of the invention; and,

FIG. 5 shows a bottom plan view of the invention. 

The ornamental design for a mechanical thermostat, as shown and described. 